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71 lines
1.5 KiB
71 lines
1.5 KiB
var assert = require('assert'),
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util = require('util'),
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spawn = require('child_process').spawn;
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// We're trying to reproduce:
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// $ echo "hello\nnode\nand\nworld" | grep o | sed s/o/a/
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var
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echo = spawn('echo', ['hello\nnode\nand\nworld\n']),
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grep = spawn('grep', ['o']),
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sed = spawn('sed', ['s/o/O/']);
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/*
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* grep and sed hang if the spawn function leaks file descriptors to child
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* processes.
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* This happens when calling pipe(2) and then forgetting to set the
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* FD_CLOEXEC flag on the resulting file descriptors.
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*
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* This test checks child processes exit, meaning they don't hang like
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* explained above.
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*/
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// pipe echo | grep
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echo.stdout.on('data', function (data) {
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if (!grep.stdin.write(data)) {
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echo.stdout.pause();
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}
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});
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grep.stdin.on('drain', function (data) {
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echo.stdout.resume();
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});
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// propagate end from echo to grep
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echo.stdout.on('end', function (code) {
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grep.stdin.end();
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});
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// pipe grep | sed
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grep.stdout.on('data', function (data) {
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if (!sed.stdin.write(data)) {
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grep.stdout.pause();
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}
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});
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sed.stdin.on('drain', function (data) {
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grep.stdout.resume();
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});
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// propagate end from grep to sed
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grep.stdout.on('end', function (code) {
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sed.stdin.end();
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});
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var result = '';
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// print sed's output
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sed.stdout.on('data', function (data) {
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result += data.toString('utf8', 0, data.length);
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util.print(data);
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});
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sed.stdout.on('end', function (code) {
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assert.equal(result, 'hellO\nnOde\nwOrld\n');
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});
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